Matrix effects in SIMS: Ion yield enhancement in copper sulfide films on copper and copper alloys

Matrix effects have been observed in positive SIMS spectra produced by Ar+ bombardment of copper sulfide films formed on copper and its alloys. The relative enhancement in copper ion yield has been measured to serve as a preliminary correction in the application of semi‐quantitative analysis of the sulfide films. Surfaces of copper, copper sulfide, and copper oxide on copper were analyzed by using both dynamic (profiling) and quasi‐static SIMS. Relative enhancement factors for copper ion yields were determined for both types of analysis. The ion yield increases in going from metal to sulfide to oxide. The enhancement factor for SIMS profiling of the sulfide films was found to be nearly constant for sulfur concentration between 30% and 10%. SIMS analysis has been performed on a sulfide film formed on a copper–zinc alloy. The enhancement factors were shown to correctly scale the signal from the sulfide film relative to that from the metal substrate, compared to simultaneous AES signal strengths.